Electrodeless self-ballasted fluorescent lamp and discharge lamp operating device

• US 6,977,472 B2
• Filed: 06/06/2003
• Issued: 12/20/2005
• Est. Priority Date: 06/07/2002
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Kominami, Satoshi, Takeda, Mamoru, Matsubayashi, Yoko, Kurachi, Toshiaki, Miyazaki, Kouji, Takahashi, Kenichiro
• Primary Examiner(s): Tran, Thuy V.
• Application Number:
  US10/494,652
• Publication Number:
  US 20040263093A1
• Time in Patent Office: 928 Days
• Field of Search: 315/224, 315/225, 315/244, 315/248, 315/291, 315/307, 315/308, 315/360, 315/DIG.4, 315/DIG.5, 315/DIG.7
• US Class Current: 315/291
• CPC Class Codes: H05B 41/2806 with semiconductor devices and specially adapted for lamps without electrodes in the vessel, e.g. surface discharge lamps, electrodeless discharge lamps
• CPC Class Codes: H05B 41/2813 Arrangements for protecting lamps or circuits against abnormal operating conditions
• CPC Class Codes: H05B 41/2853 against abnormal power supply conditions
• CPC Class Codes: H05B 41/3921 with possibility of light intensity variations
• CPC Class Codes: H05B 41/3924 by phase control, e.g. using a triac H05B41/3922 takes precedence
• CPC Class Codes: H05B 41/3927 by pulse width modulation H05B41/3922 takes precedence
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
• CPC Class Codes: Y10S 315/04 Dimming circuit for fluorescent lamps

Abstract

An electrodeless self-ballasted fluorescent lamp includes an electrodeless fluorescent lamp 3, a ballast circuit 4 and a lamp base which are formed as one unit. The ballast circuit 4 includes: an AC-DC converter 5; a DC-AC converter 6 formed so as to intermittently drive the electrodeless fluorescent lamp 3; and a dimming controller 7 formed so as to detect the turn-on of a phase-controlled AC voltage and output an intermittent command signal for changing the ratio between an operating period and an extinguishing period to the DC-AC converter 6. Furthermore, the dimming controller 7 is formed so as to output a signal for extinguishing the electrodeless fluorescent lamp 3 before the operation thereof becomes unstable.

Claims

1. An electrodeless self-ballasted fluorescent lamp comprising:

an electrodeless fluorescent lamp;

a ballast circuit for applying a high-frequency voltage to the electrodeless fluorescent lamp; and

a lamp base electrically connected to the ballast circuit,

wherein the electrodeless fluorescent lamp, the ballast circuit and the lamp base are formed as one unit,

wherein the ballast circuit comprises;

an AC-DC converter for converting a phase-controlled AC voltage into a DC voltage;

a DC-AC converter for converting the DC voltage into a high-frequency voltage, the DC-AC converter being formed so as to intermittently drive the electrodeless fluorescent lamp due to the existence of an operating period during which the high-frequency voltage is applied to the electrodeless fluorescent lamp so that the electrodeless fluorescent lamp is operated, and an extinguishing period during which the generation of the high-frequency voltage is stopped so that the electrodeless fluorescent lamp is extinguished; and

a dimming controller formed so as to detect the turn-on of the phase-controlled AC voltage and output an intermittent command signal that changes the ratio between the operating period and the extinguishing period to the DC-AC converter, and

wherein the dimming controller is formed so as to output a signal for extinguishing the electrodeless fluorescent lamp before the operation thereof becomes unstable.

2. The electrodeless self-ballasted fluorescent lamp of claim 1, wherein the dimming controller comprises:

a first dimming control signal input section and a second dimming control signal input section;

a sawtooth wave generator for generating a sawtooth wave; and

a dimming command signal generator for generating a dimming command signal,

wherein the first dimming control signal input section is connected to the sawtooth wave generator via a photo coupler, and

wherein the second dimming control signal input section is connected to the dimming command signal generator.

3. The electrodeless self-ballasted fluorescent lamp of claim 2, wherein the sawtooth wave generator and the dimming command signal generator are connected to a comparator.

4. The electrodeless self-ballasted fluorescent lamp of claim 1, wherein the dimming controller is further formed so as to output a signal for synchronizing the timing of the turn-on with that of the operation of the lamp intermittently driven by the DC-AC converter.

5. The electrodeless self-ballasted fluorescent lamp of claim 1, wherein the dimming controller has a sawtooth wave generator comprising a differentiating circuit that comprises a capacitor and a resistor,

wherein the differentiating circuit is connected to a collector terminal of a transistor for generating a pulse wave synchronized with the turn-on and turn-off of the phase-controlled AC voltage,

wherein an output terminal of the differentiating circuit is connected with an anode of a diode, while a cathode of the diode is connected with a base terminal of a transistor for discharge,

wherein an emitter terminal of the transistor for discharge is connected with a diode for potential adjustment, and

wherein a capacitor for charge and discharge is connected between the emitter terminal and collector terminal of the transistor for discharge, thus allowing the generation of a sawtooth wave synchronized with the turn-on of the phase-controlled voltage.

6. The electrodeless self-ballasted fluorescent lamp of claim 1, wherein the phase-controlled AC voltage is an output voltage of a dimmer which has been phase-controlled by the dimmer.

7. A discharge lamp operating device comprising:

a discharge lamp;

an AC-DC converter for converting a phase-controlled AC voltage into a DC voltage;

a DC-AC converter for converting the DC voltage into a high-frequency voltage, the DC-AC converter intermittently driving the discharge lamp due to the existence of an operating period during which the high-frequency voltage is applied to the discharge lamp so that the discharge lamp is operated, and an extinguishing period during which the generation of the high-frequency voltage is stopped so that the discharge lamp is extinguished; and

a dimming controller for detecting the turn-on of the phase-controlled AC voltage and for outputting an intermittent command signal that changes the ratio between the operating period and the extinguishing period to the DC-AC converter,

wherein the discharge lamp is an electrodeless discharge lamp, and

wherein the dimming controller is formed so as to output a signal for extinguishing the discharge lamp before the operation thereof becomes unstable.

8. The discharge lamp operating device of claim 7, wherein the dimming controller is further formed so as to output a signal for synchronizing the timing of the turn-on with that of the operation of the lamp intermittently driven by the DC-AC converter.

9. The discharge lamp operating device of claim 7, wherein the discharge lamp has a discharge bulb having a recessed portion, and

wherein an induction coil is inserted into the recessed portion of the discharge bulb.